**4. Ethological control: pheromones and their use in mating disruption (MD)**

Pheromones are volatile chemical messengers released into the environment which can influence the behavior of other individuals of the same species at a distance. They are secreted by individuals via their exocrine glands. They are highly specific at the species level, affecting insects' aggregation, dispersion, alarm and sexual behavior [23].

In the exocrine glands of female *L. botrana* specimens, a linear hydrocarbon chain of 15 carbons have been identified which present acetate and alcohols as functional groups. The principal pheromone compound among these is (E, Z) -7,9 dodecadienyl acetate. *L. botrana* can sense and respond to this compound in a wide range of concentrations between 0.1–2500 ng [24, 25].

The chemical attractant capacities of this pheromone lead to its use as a tool for monitoring adult male *L. botrana* specimens. Monitoring is done via counting captured males which are trapped on the sticky surfaces of female pheromone traps (**Figure 6**). Female pheromone use also allows us to control pest populations via MD. This strategy consists of interfering with insects' olfactory chemical communication via mass distribution of synthetic pheromones in the field with MD dispensers. This creates a pheromone cloud which disorients and confuses the males and keeps them from finding females, thereby impeding mating and reducing pest populations [23]. The MD strategy relies on two different mechanisms: one is competition between females and MD dispensers in attracting males; and the other is based on camouflaging the olfactory track which have on females. Commercial MD dispensers, carry the compound (E, Z) -7,9- dodecadienyl acetate, which is progressively sprayed into the farming environment for a determined period of time. The release rate for each unit is generally 50–60 μg/h [26].

When applying this method, pest population density must be considered, as it is more effective with a lower adult population density. Above a certain density, mating is not interrupted regardless of ambient pheromone concentrations; the critical density for *L. botrana* is 4000 couples per hectare, and beyond this population density, the effectiveness of MD drops drastically [20]. Furthermore, when bunches are infested at a rate of 5–10% during the first generation, the effectiveness of MD in following generations is greatly reduced [21, 27, 28].

For MD to be effective, 500 sexual MD dispenser per hectare must be installed in vineyards before the first seasonal flight begins. MD dispenser must be uniformly distributed around the vineyard and attached to shoots so that foliage protects them from direct sunlight exposure and high temperatures [23]. To compensate for atmospheric pheromone dilution around lot perimeters, twice as many MD dispenser must be placed along property edges [29].

**Figure 6.** *Ethological control. A, traps baited with synthetic lures. B, MD emitter for* L. botrana *control.*

MD efficacy evaluation is done by checking the presence of adults and larvae via field monitoring and follow-up. Catching males in traps baited with synthetic lures is considered the easiest way to evaluate MD effectiveness. Capturing no males in traps is considered a "necessary but insufficient" indicator of effective MD, since the pheromone quantity necessary to interrupt males' orientation towards traps baited with synthetic lures is lower than the amount needed to disrupt mating [30]. Thus, capturing a few males in the same trap indicates a high risk of MD control strategy failure. The reliability of traps for monitoring adults might be increased by the use of high-dose lures. In other hand, monitoring of this pest and its damages can be done in the vineyard to determine infestation rate. For this, the following variables must be considered: percentage of bunches infested, number of larvae per inflorescence, number of eggs, larvae and damaged grapes per bunch. The mean number of larvae per bunch gives the most precise evaluation of meting disruption effectiveness, while the number of larvae per inflorescence (i.e., the number of first-generation larvae) can be very quickly evaluated in the field. Precise larval population estimates during the second and third generation require destructive sampling and dissection which take significant time, especially for varietals with compact grape bunches. Sexual confusion evaluations based on final crop damage can be deceptive because this damage, especially primary and secondary rotting, may be due to factors apart from larva feeding [30].

Finally, it must be noted that employing MD has many advantages, including being an ecologically clean method which leaves no wastes, is targeted and does not alter the ecosystem. Finally, it has a cumulative effect through the years, along with being comfortable to apply [23].

### **5. Biological control: natural enemies**

An alternative to chemical control is using natural enemies such as "parasites and predators". Around 21 species have been described as preying on *L. botrana*, belonging to the following orders: Neuroptera, Coleoptera (coccinelids, carabids, clerids, malachiinae), Dermaptera, Hymenoptera, and Hemiptera. In laboratory tests, the predator *Chrisoperla defreitasi* (Neuroptera*:* Chrysopidae) has been observed eating eggs, larvae and pupae of *L. botrana* [23].

97 species of insects can parasitize *L. botrana* [31], belonging to the families Tachinidae (**Figure 7A**), Ichneumonidae, Pteromalidae and Chalcididae, among others. Among the ichneumenoid parasites, *Campoplex capitator* stands out due to its natural efficiency, density and wide geographic distribution. It has been regularly found in most European vineyards (Italy, Spain, Switzerland and France). *C. capitator* parasitizes *L. botrana* pupae in diapause. Freeing them en masse at the start of the season could reduce reproduction of later generations of this pest. *Trichogramma* spp. are microhymenopteras which act on eggs (egg-eating parasites) (**Figure 7B** and **C**). Their action has the advantage of controlling this pest before it can cause harm. In laboratory tests, 95% parasitism has been achieved. Freeing them en masse (thousands of micro-wasps per week) in the field could be useful for egg control. To use these parasites, it is important to monitor adult moths present in the field in order to effectively control eggs. Similarly, Ichneumonidae (**Figure 7D** and **F**) can be a good alternative for controlling *L. botrana*, as they attack larvae and pupae of a wide variety of insects. *Dibrachys affinis* Masi, which belongs to the Pteromalidiae family, also acts upon *L. botrana* chrysalises, reaching parasitism rates of 88%. The ectoparasite *Apanteles* sp. has been noted in the larval stage of *L. botrana.* (**Figure 6**). It has the advantage of global distribution [23].

*Integrated Pest Management of* Lobesia botrana *with Microorganism in Vineyards… DOI: http://dx.doi.org/10.5772/intechopen.99153*

#### **Figure 7.**

*Natural enemies for controlling* L. botrana. *A, adult* Phytomyptera nigrina *(Diptera:Tachinidae) emerging from* L. botrana *pupa. B,* Trichogramma sp. *parasitizing egg. C,* L. botrana *eggs parasitized by* Trichogramma*. D, adult Ichneumonidae. E, adult Ichneumonidae parasitizing* L. botrana *pupa. F, adult* Apanteles *sp.*
